have you tried a sitz bath? might help relieve some of the pain and discomfort you're having at the moment...also make sure you're taking enough of the laculose that your stool is soft-runny, this will take away some of the pressure.
No straining/ sitting on the toilet for too long! Or even sitting down for long periods at all as this also causes pressure in that area.
You may not need an op at all...depends how long this has been a problem for you and external piles can be treated with sclerotherapy